ABSTRACT
Alternanthera philoxeroides is a promising species in the search for new molecules with biological effects. To accelerate this bioprospection process of A. philoxeroides, the chosen methods (allelopathy and discdiffusion technique) are excellent alternatives. The purpose of this study was to evaluate the allelopathic effects and verify the antibacterial properties of extracts from A. philoxeroides. To evaluate the antibacterial activity, disc diffusion technique was used with five reference strains. The germination test was conducted with the extracts at concentrations of 0, 1.0, 2.0 e 3.0 mg mL-1 in a petri dish with 30 lettuce seeds and for the growth trial 10 seeds were used. The experimental design was completely randomized in factorial 4 × 2 × 4 (four extracts, two sources, four concentrations), with four replicates.The results indicate that the lettuce germination was influenced by ethyl acetate fraction obtained from leaves of A. philoxeroides at the highest concentrations; however, the germination speed and the radicle growth were significantly affected by all the extracts starting at 1mg mL-1 concentration. Those results demonstrate allopathic effect of different extracts of this plant, although they have not interfered with the strains growth used in this experiment.
Keywords:
alellopathy; alligator weed; disc diffusion; germination